KDP晶体单点金刚石车削表面形貌分形分析

 分别使用2维和3维分形方法对单点金刚石车削加工的KDP晶体表面形貌进行了分析，并对表面的3维分形维数和3维粗糙度表征参数进行了比较，分析了二者对表面形貌表征的差异。使用2维轮廓分形方法计算了KDP晶体表面圆周各方向上的分形维数。通过分析得出：3维分形维数与表面粗糙度值成反比关系；使用单点金刚石车削方法加工KDP晶体会形成各向异性特征明显的已加工表面，在一定程度上容易形成小尺度波纹；已加工表面是否具有明显的小尺度波纹特征与表面粗糙度值并无直接关系，但与其表面轮廓分形状态分布密切相关；KDP晶体表面2维功率谱密度与其分形状态具有相近的方向性特征。     

溅射过程中粒子能量对钛薄膜表面形貌影响

借助于原子力显微镜研究了离子束溅射沉积工艺中入射离子能量对制备的Ti薄膜表面形貌的影响。对薄膜表面高度数据进行相关运算，发现在此工艺条件下制备的薄膜具有典型的分形特征，利用分形表面高度—高度相关函数的唯象表达形式对不同能量下制备Ti薄膜表面的高度相关函数进行拟合。得到了薄膜表面的分形维数、水平相关长度、标准偏差粗糙度等参量。研究发现，入射Ar离子能量在300—700eV之间薄膜表面的粗糙度随着沉积粒子的能量增加而增大，分形维数随着入射离子能量的增加而减少。另外，在得到的分形维数基础上对不同溅射电压下Ti薄膜的生长机制进行了初步研究。     

溅射功率对Mo薄膜微结构和性能的影响

 实验采用直流磁控溅射沉积技术在不同溅射功率下制备Mo膜,研究了不同溅射功率下Mo膜的沉积速率、表面形貌及晶型结构,并对其晶粒尺寸和应力进行了研究。利用原子力显微镜观察样品的表面形貌发现随着溅射功率的增加,薄膜表面粗糙度逐渐增大。X射线衍射分析表明薄膜呈立方多晶结构,晶粒尺寸为14.1～17.9 nm;应力先随溅射功率的增大而增大,在40 W时达到最大值(2.383 GPa),后随溅射功率的增大有所减小。     

溅射粒子能量对金属Mo薄膜表面特性的影响

利用原子力显微镜研究了不同溅射离子能量对Mo薄膜表面形貌的影响.利用特殊设计的夹具，在同一真空内完成所有薄膜样品的制备，减少了多次沉积过程对薄膜生长特性的影响 .对原子力显微镜测量得到的表面高度数据进行相关运算，从统计角度定量地研究了不同沉积能量下Mo薄膜表面特性.结果表明，薄膜表面具有典型的分形特征，在相关运算的基础上给出表面的分形维数、水平相关长度、界面宽度等参数.其中，屏栅电压为500V时制备 的薄膜样品与300和700?V时制备的薄膜样品表面的界面宽度及水平相关长度具有倍数差别，但三种溅射电压下薄 关键词： 离子束溅射 钼 薄膜 分形     

溅射功率对直流磁控溅射Ti膜结构的影响

 采用直流磁控溅射方法制备了纯Ti膜，研究了不同功率下Ti膜的沉积速率、表面形貌及晶型结构，并对其应力进行了研究。研究表明：薄膜的沉积速率随溅射功率的增加而增加，当溅射功率为20 W时，原子力显微镜(AFM)图像显示Ti膜光洁、致密，均方根粗糙度最小可达0.9 nm。X射线衍射(XRD)分析表明薄膜的晶体结构为六方晶型，Ti膜应力先随溅射功率增大而增大，在60 W时达到最大值（为945.1 MPa），之后随溅射功率的增大有所减小。     

高择优取向Mo薄膜的直流磁控溅射制备及其电学性能

使用直流磁控溅射法在玻璃基底上沉积Mo薄膜,采用X射线衍射仪、原子力显微镜和四探针测试系统研究了溅射工艺对Mo薄膜的结构、形貌和电学性能的影响.结果表明:当基片温度为150 ℃时,薄膜获得(211)晶面择优取向生长,而在低于250 ℃的其它温度条件下,样品则表现为(110)晶面择优取向生长.进一步的表面形貌分析显示:薄膜的粗糙度随基片温度变化不明显,其值大约为0.35 nm,随溅射功率密度的增大而变大|电学性能方面:随着溅射功率密度的升高,薄膜导电性能迅速增强,电阻率呈现近似指数函数衰减|随着基底温度的升高,薄膜的电阻率先减小后增大,当基底温度为150 ℃时,薄膜电阻率降低至最小值2.02×10-5 Ω·cm.     

射频溅射Pd薄膜的电阻率研究

本文研究了溅射Pd薄膜的电阻率与膜厚关系和不同溅射功率下Pd薄膜电阻率,结果表明,电阻率与膜厚的关系与现有的薄膜电阻率尺寸效应的理论基本相符,存在的差异主要是由溅射对衬底温度影响而引起的,并显示玻璃衬底上生长膜也有择优取向,溅射功率的变化对电阻率有一定的影响,进一步讨论溅射过程中衬底温度变化的问题,得出膜电阻率随衬底温度变化的定量关系式。 关键词：     

基于小波变换Cu-W薄膜表面形貌表征与硬度值分散性评价

提出了一种基于小波变换描述薄膜表面形貌的方法.运用离散小波变换法研究磁控溅射Cu-W薄膜表面特征随溅射时间的演变.结果表明，Cu-W薄膜在溅射时间超过600s时才达到稳定.不同薄膜表面形貌的变化主要是由高频部分引起.薄膜的粗糙表面会引起纳米压入硬度值的分散，这种分散性可用基于小波变换的薄膜表面形貌多尺度分解评价. 关键词： Cu-W 薄膜 表面形貌 小波变换 纳米压入     

用离子束溅射方法制备的钛薄膜表面形貌分析

用离子束溅工艺在K9玻璃基片上沉积Ti薄膜，并用原子力显微镜对其表面形貌进行测量，通过数值相关运算，发现在此工艺条件下薄膜生长界面为各向同性的自仿射分形表面，并用粗糙指数、横向相关长度和标准偏差粗糙度对薄膜样品表面进行定量描述。利用自仿射分形表面的相关函数对数值运算的结果进行拟合，得出Ti薄膜生长界面的粗糙度指数α＝0．72，相应的分形维数Df＝2．28，并由此得到在离子束溅射工艺下Ti薄膜屑于守恒生长的结论，其生长动力学过程可用Kuramoto—Sivashinsky方程来描述。     

金属互连电迁移噪声的分形特征

为了研究金属互连电迁移失效机理并寻找新的电迁移表征参量，应用分形理论，通过电子扩散轨迹分形维数，将电迁移噪声时间序列分形维数与晶粒间界分形维数相联系，确定了噪声时间序列分形维数在电迁移演变中的变化趋势.研究结果表明，在金属互连电迁移前期，晶粒间界形貌越来越复杂，致使噪声时间序列的分形维数逐渐增大；成核后，由于空位凝聚成空洞，晶粒间界形貌变得较成核前规则，致使噪声时间序列的分形维数减小；成核时刻是其折点.实验结果证明理论分析的正确性，噪声时间序列的分形维数可望作为金属互连电迁演变的表征参量.     

Fractal properties of aggregates of metal nanoclusters on solid surface

AFM images are used to determine and analyze fractal characteristics (cluster fraction dimension and lacunarity) of aggregates of Au and Ag nanoclusters on metal films of the same metal produced with the aid of thermal vacuum deposition on mica surface. A fractal dimension of 1.6 that corresponds to typical samples with relatively uniform distribution of nanoclusters on the film surface is in agreement with the mean value calculated from experimental data of Belko et al., who studied the fractal dimension of Au nanoclusters on a different dielectric (quartz) surface. When a compact single aggregate of Au nanoclusters is formed on a certain active center or defect, the fractal cluster dimension decreases to 1.4. The experimental data are compared with the results of existing theoretical models of association of nanoclusters in 2D systems.     

Growth of TiN films at low temperature

Thermodynamic analysis on growth of TiN films was given. The driving force for deposition of TiN is dependent on original Ti(g)/N(g) ratio and original partial pressure of N(g). TiN films were deposited by ion beam assisted electron beam evaporation system under suitable nitrogen gas flow rate at 523 K while the density of plasma varied with diverse discharge pressure had been investigated by the Langmuir probe. TiN films were characterized by means of Fourier transform infrared absorption spectrum (FTIR), X-ray diffraction (XRD) and observed by means of atom force microscopy (AFM). The results of these measurements indicated preferential TiN(1 1 1) films were deposited on substrate of Si(1 0 0) and glass by ion beam assisted electron beam evaporation system at low temperature, and it was possible for the deposition of TiN films with a preferential orientation or more orientations if the nitrogen gas flow rate increased enough. Sand Box was used to characterize the fractal dimension of surface of TiN films. The results showed the fractal dimension was a little more than 1.7, which accorded with the model of diffusion limited aggregation (DLA), and the fractal dimension of TiN films increased with increase of the temperature of deposition.     

Physical and electrochemical properties of Li-intercalated Sn oxide films made by sputtering

Sn oxide films were made by reactive rf magnetron sputtering under conditions that led to both electronic and ionic conductivity. The film structure was studied by X-ray diffraction and Atomic Force Microscopy (AFM). Li⁺ intercalation produced electrochromism with coloration efficiency peaked in the infrared. Cyclic voltammograms taken at different sweep rates were interpreted in terms of a unique structural parameter related to the fractal dimension of a self-affine surface relief and in excellent agreement with the fractal dimension as obtained with AFM. Mössbauer spectroscopy was used to determine the valence state of the Sn-atoms; a change from Sn⁴⁺ to Sn²⁺ was detected after electrochemical intercalation of Li⁺.     

Application of Mie theory and fractal models to determine the optical and surface roughness of Ag–Cu thin films

Thin films of Ag/Cu were deposited by reactive DC magnetron sputtering on (001)-oriented Si and glass substrates for various deposition times (4–24 min). These films were characterized by atomic force microscopy (AFM), and a power law scaling was performed on the obtained micrographs to investigate the self-affine nature of the sample morphology, which is indicative of a fractal structure. We applied the Higuchi’s algorithm to the AFM data to determine the fractal dimension of each sample, and the Hurst exponents were computed. The deposition time dependences of these parameters and the grain size distributions estimated from the UV–visible spectra using the Mie theory, allowed us to describe a particle formation mechanism during the deposition process, in which the length of continuous paths of conductive particles increases as the deposition time is increased. In agreement with this explanation, the electrical resistance decreased with the increment of the deposition time.     

Fractal properties of macrophage membrane studied by AFM

Complexity of cell membrane poses difficulties to quantify corresponding morphology changes during cell proliferation and damage. We suggest using fractal dimension of the cell membrane to quantify its complexity and track changes produced by various treatments. Glutaraldehyde fixed mouse RAW 264.7 macrophage membranes were chosen as model system and imaged in PeakForce QNM (quantitative nanomechanics) mode of AFM (atomic force microscope). The morphology of the membranes was characterized by fractal dimension. The parameter was calculated for set of AFM images by three different methods. The same calculations were done for the AFM images of macrophages treated with colchicine, an inhibitor of the microtubule polymerization, and microtubule stabilizing agent taxol. We conclude that fractal dimension can be additional and useful parameter to characterize the cell membrane complexity and track the morphology changes produced by different treatments.     

Comparison of fractal analyses methods and fractal dimension for pre-treated stainless steel surfaces and the correlation to adhesive joint strength

The fractal dimensions of six differently mechanically pre-treated stainless steel samples were investigated using five fractal algorithms. The surfaces were analyzed using a profiler, atomic force microscopy (AFM), scanning electron microscopy (SEM) and light microscopy (LM), and thereafter adhesively bonded and tested in single-overlap joints to test their tensile strength. All samples showed different fractal behavior, depending on the microscopic methods and fractal algorithms. However, the overall relation between fractal dimension and tensile strength is qualitatively the same, except for the SEM images. This verifies that tensile strength is correlated to fractal dimension, although only within the length-scale of the profiler and the light microscope (≈0.5–100 μm). The AFM method was excluded in this comparison, since the limitation in the z-direction for the AFM scanner made it difficult to scan the rougher parts of the blasted samples. The magnitude of the surfaces is a parameter not often considered in fractal analysis. It is shown that the magnitude, for the Fourier method, is correlated to the arithmetic average difference, R_a, but only weakly to the fractal dimension. Hence, traditional parameters, such as R_a, tell us very little about the spatial distribution of the elevation data. Received: 22 December 1999 / Accepted: 9 October 2000 / Published online: 9 February 2001     

Morphological characterization of ITO thin films surfaces

In this study, indium tin oxide (ITO) thin films were deposited by electron beam evaporation method on glass substrates at room temperature, followed by postannealing at 200 and 300 °C for annealing time up to 1 h. Fractal image processing has been applied to describe the surface morphology of ITO thin films from their atomic force microscopy (AFM) images. These topographical images of the ITO thin films indicate changes in morphological behavior of the film. Also, the results suggest that the fractal dimension D can be used to explain the change of the entire grain morphology along the growth direction.     

Surface characterization and microstructure of ITO thin films at different annealing temperatures

In this study, the electron beam evaporation method is used to generate an indium tin oxide (ITO) thin film on a glass substrate at room temperature. The surface characteristics of this ITO thin film are then investigated by means of an AFM (atomic force microscopy) method. The influence of postgrowth thermal annealing on the microstructure and surface morphology of ITO thin films are also examined. The results demonstrate that the film annealed at higher annealing temperature (300 °C) has higher surface roughness, which is due to the aggregation of the native grains into larger clusters upon annealing. The fractal analysis reveals that the value of fractal dimension D_f falls within the range 2.16-2.20 depending upon the annealing temperatures and is calculated by the height-height correlation function.     

竖壁液膜流壁面热流率对流动影响的实验研究

本文用相空间重构的方法,对竖壁薄液膜流动的液膜厚度时间序列进行了重构,并用分维数对奇怪吸引子的动力特征进行了描述,由此描述了壁面热流率对竖壁薄液膜流动特性的影响。